Active multifocal lens

ABSTRACT

An optical lens device has an actively controllable focal length. This device comprises an element with lensing effect comprising a plurality of regions. Each such region has a corresponding refractive power for providing a corresponding focal length distinct from the focal length of at least one other region of this plurality of regions. The device further comprises at least one non-centric addressable optical element integrated in or provided on the element with lensing effect. This at least one addressable optical element is adapted for changing the transmittance of at least one of the plurality of regions in response to a control signal. The device also comprises a control means for generating the control signal.

FIELD OF THE INVENTION

The invention relates to the field of multifocal and varifocal opticallenses. More specifically it relates to an optical lens having anactively controllable focal length, for example for ophthalmicapplications.

BACKGROUND OF THE INVENTION

An ophthalmic lens, such as a contact lens or an intra-ocular lens,provides vision correction by introducing a refractive element into theoptical line of sight. A conventional ophthalmic lens may provide afixed correction of the dioptric power of an eye. For example, anoptical design is determined taking into account information gatheredfrom the patient, and the lens is manufactured according to thispersonalized design, e.g. by cast molding or lathing. The opticalqualities of such a conventional lens thus are static once the lens hasbeen formed.

However, many people suffer from presbyopia, which means that they havetrouble accommodating of vision, e.g. their eyes have a limited focalrange or changing focus between nearby and remote sceneries takes a longtime. Presbyopia is common among people above the age of 40-50 and mayfor example be caused by a decreased elasticity of the intraocular lensused for accommodation of vision. Bifocal or ‘progressive’ spectaclescan provide different dioptric corrections that correct the sight fordifferent viewing distances. This is accomplished by dividing the lensesinto juxtaposed zones with different dioptric powers, either with asharp or a gradual transition between these zones. The desired dioptricpower is then selected by moving the line of sight so that it crossesthe appropriate zone of the spectacle's lens. However, in a contactlens, since it is in direct contact with the eye, it is not easy to movethe line of sight and therefore a multifocal contact lens is not easy toimplement. For example, a translational dual focal contact lens is knownin the art, in which the wearer can shift the lens upward or downwardusing eye ball movements in order to select a different dioptric zone inthe lens. However, the learning curve of such a lens is very steep andits use is not at all obvious, especially for older people. Furthermore,for intra-ocular lens implants, shifting the lens with respect to theline of sight may be infeasible.

In order to overcome the limitations of conventional contact lenses,dual focal contact lenses are known in the art. In such dual focalcontact lenses, two dioptric powers are simultaneously active, leadingto two superimposed images, one focused nearby and one remotely focused.However, this has the disadvantage of vision artefacts, such as halos,ghost vision and reduced contrast. Furthermore, dual focal or multifocalcontact lenses are known in the art having a plurality of substantiallyconcentric lens zones with different, possibly alternating lens powers.Although such lenses may also lead to superimposed images focused ondifferent distances, due to the concentric arrangement of the lenszones, the effective lens powers will to a certain degree depend on thediameter of the pupil, although there is some optical distance betweenthe latter and the lens. In bright circumstances the pupil diameter issmall and the central part of the lens will determine its effectivepower. In dim lighting circumstances, the pupil dilates, and theinfluence of the outer rings will be relatively higher. However, thedisadvantage of this approach is that there is no guaranteedrelationship between pupil diameter and desired lens power. Furthermore,such lens may also be susceptible to vision artefacts such as halos,ghost vision and reduced contrast.

Another approach known in the art involves a lens with an aspheric frontor back surface which provides a smooth transition between differentfocal points from the middle of the lens towards the edge. In such adesign the lens operation is also pupil size dependent to a certaindegree. Again, such lenses have the disadvantage of being prone tohalos, ghost vision and reduced contrast.

Active lenses are also known in the art. For example, U.S. Pat. No.8,348,424 discloses an ophthalmic lens with a variable optic portion,which is capable of changing the optical quality of the lens, e.g. acast molded silicone hydrogel contact lens with an energized variableoptic insert. Such variable optic insert can for example comprise aliquid meniscus lens with an electrically conducting fluid and oilcapable of changing an optical characteristic of the ophthalmic lens.

Furthermore, U.S. Pat. No. 8,348,422 also discloses an energizedophthalmic lens. Embodiments according to U.S. Pat. No. 8,348,422 maycomprise activating components within an ophthalmic lens system inresponse to an external signal, e.g. an eyelid blink or a pressuresignal applied to the lens via the closed eyelid.

SUMMARY OF THE INVENTION

It is an object of embodiments of the present invention to provideefficient and good means for variable focal length control, e.g. forselecting a focus, in a multifocal or varifocal lens. In someembodiments of the present invention, efficient and good means forvariable focal length control are obtained even at changing lightintensity variations.

It is an advantage of embodiments of the present invention that asolution is provided being substantially insensitive to a diaphragmselection, e.g. to the variable pupil diameter for an ophthalmic contactlens.

It is an advantage of embodiments of the present invention that they canbe applied in an optical apparatus such as a photographic camera, forexample to enable switching the optical apparatus between differentfocal distances, e.g. for zooming, without requiring mechanically movingparts such as moving lens groups.

It is an advantage of embodiments of the present invention that they canbe applied for human vision correction, for example for implementationin a contact lens or in an implantable lens, e.g. an intra-ocular lens.

It is an advantage of embodiments of the present invention thatcorrection of the vision can be obtained that are less or not prone toimage artefacts such as halos, ghost vision and reduced contrast.

The above objective is accomplished by a method and device according tothe present invention.

It is an advantage of embodiments of the present invention that simpleand efficient focus control is provided for ophthalmic lenses, e.g. fora contact lens or intra-ocular lens.

The present invention relates to an optical lens device having anactively controllable focal length, comprising an element with lensingeffect comprising a plurality of regions, each region having acorresponding refractive power for providing a corresponding focallength distinct from the focal length of at least one other region ofsaid plurality of regions, at least one addressable optical elementintegrated in or provided on the element with lensing effect, the atleast one addressable optical element being adapted for changing thetransmittance of at least one of said plurality of regions in responseto a control signal, and a control means for generating said controlsignal.

The at least one addressable optical element may be a non-concentricarea. The non-concentric area may be a non circle-symmetric sector ofthe optical element with lensing effect. The non-concentric area maycomprise one or more sector regions of the optical element with lensingeffect. The one or more sector regions may be pie-slice shaped, e.g.having their pie-point in the center of the optical element with lensingeffect. The optical lens device may be adapted for use as an ophthalmiccontact lens or an intra-ocular implant.

The shape and arrangement of the at least one addressable opticalelement may be determined by the shape and arrangement of the pluralityof regions of the element with lensing effect.

A corresponding addressable optical element may be provided in or oneach of said plurality of regions.

The element with lensing effect may be made of rigid gas permeable orsoft material.

The at least one addressable optical element may comprise an addressableoptical element configured as a sector of the element with lensingeffect.

The at least one addressable optical element may cover an area which issubstantially less than the total area of the element with lensingeffect.

The at least one addressable optical element may comprise overlappinglayers.

The at least one addressable optical element may comprise a liquidcrystal technology element.

The at least one addressable optical element may comprise a bistable ormultistable element.

The at least one addressable optical element may comprise an energysupply.

The present invention also relates to a method for controlling the focallength of an optical lens device, comprising providing an element withlensing effect comprising a plurality of regions, each region having acorresponding refractive power for providing a corresponding focallength distinct from the focal length of at least one other region ofsaid plurality of regions, and changing the transmittance of at leastone of said plurality of regions by controlling at least onenon-concentric addressable optical element integrated in or provided onthe element with lensing effect.

The present invention also relates to the use of an optical lens deviceas described above for human vision correction.

In another aspect, the present invention relates to an optical lensdevice having an actively controllable focal length, comprising anelement with lensing effect comprising a plurality of regions, eachregion having a corresponding refractive power for providing acorresponding focal length distinct from the focal length of at leastone other region of said plurality of regions, at least one addressableoptical element integrated in or provided on the element with lensingeffect, the at least one addressable optical element being adapted forchanging the transmittance of at least one of said plurality of regionsin response to a control signal, and a control means for generating saidcontrol signal, the at least one addressable optical element having alens surface area being at least 10%, e.g at least 15%, e.g. at least20% of the surface area of the optical element with lensing effect.

According to embodiments of this aspect of the present invention, the atleast one addressable optical element integrated in or provided on theelement with lensing effect may have any suitable shape such as one ormore sectors, concentric, disk shaped.

The optical system may furthermore comprise one or more featurescorresponding with features of an optical system as described for thefirst aspect.

Particular and preferred aspects of the invention are set out in theaccompanying independent and dependent claims. Features from thedependent claims may be combined with features of the independent claimsand with features of other dependent claims as appropriate and notmerely as explicitly set out in the claims.

These and other aspects of the invention will be apparent from andelucidated with reference to the embodiment(s) described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a frontal view of an optical lens device according toembodiments of the present invention.

FIG. 2 shows a transversal view of the optical lens device shown in FIG.1, according to embodiments of the present invention.

FIG. 3 shows a simple illustrative embodiment of an optical lens deviceaccording to embodiments of the present invention.

FIG. 4 illustrates the selection of a first focus in the optical lensdevice shown in FIG. 3, according embodiments of the present invention.

FIG. 5 illustrates the selection of a second focus in the optical lensdevice shown in FIG. 3, according embodiments of the present invention.

FIG. 6 shows a concentric arrangement of regions of the element withlensing effect of an optical lens device according to a first exemplaryembodiment of the present invention.

FIG. 7 shows a sectorial arrangement of regions of the element withlensing effect of an optical lens device according to a second exemplaryembodiment of the present invention.

FIG. 8 shows an optical lens device according to embodiments of thepresent invention in which the total area spanned by the at least oneaddressable optical element is smaller than the surface area of theelement with lensing effect.

FIG. 9 shows an optical lens device according to embodiments of thepresent invention, which comprises only a single addressable opticalelement.

FIG. 10 shows a transversal view of the optical lens device shown inFIG. 9, according to embodiments of the present invention.

FIG. 11 shows a device according to another embodiment of the presentinvention, having an aspheric multifocal design and an array ofaddressable optical elements.

FIG. 12 shows a transversal view of the optical lens device shown inFIG. 11, according to embodiments of the present invention.

FIG. 13 shows an optical lens device according to embodiments of thepresent invention comprising addressable optical elements arranged inconcentric addressable rings.

FIG. 14 shows a transversal view of the optical lens device shown inFIG. 13, according to embodiments of the present invention.

FIG. 15 illustrates an exemplary method according to embodiments of thepresent invention.

The drawings are only schematic and are non-limiting. In the drawings,the size of some of the elements may be exaggerated and not drawn onscale for illustrative purposes.

Any reference signs in the claims shall not be construed as limiting thescope.

In the different drawings, the same reference signs refer to the same oranalogous elements.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The present invention will be described with respect to particularembodiments and with reference to certain drawings but the invention isnot limited thereto but only by the claims. The drawings described areonly schematic and are non-limiting. In the drawings, the size of someof the elements may be exaggerated and not drawn on scale forillustrative purposes. The dimensions and the relative dimensions do notcorrespond to actual reductions to practice of the invention.

Furthermore, the terms first, second and the like in the description andin the claims, are used for distinguishing between similar elements andnot necessarily for describing a sequence, either temporally, spatially,in ranking or in any other manner. It is to be understood that the termsso used are interchangeable under appropriate circumstances and that theembodiments of the invention described herein are capable of operationin other sequences than described or illustrated herein.

Moreover, the terms top, under and the like in the description and theclaims are used for descriptive purposes and not necessarily fordescribing relative positions. It is to be understood that the terms soused are interchangeable under appropriate circumstances and that theembodiments of the invention described herein are capable of operationin other orientations than described or illustrated herein.

It is to be noticed that the term “comprising”, used in the claims,should not be interpreted as being restricted to the means listedthereafter; it does not exclude other elements or steps. It is thus tobe interpreted as specifying the presence of the stated features,integers, steps or components as referred to, but does not preclude thepresence or addition of one or more other features, integers, steps orcomponents, or groups thereof. Thus, the scope of the expression “adevice comprising means A and B” should not be limited to devicesconsisting only of components A and B. It means that with respect to thepresent invention, the only relevant components of the device are A andB.

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure or characteristicdescribed in connection with the embodiment is included in at least oneembodiment of the present invention. Thus, appearances of the phrases“in one embodiment” or “in an embodiment” in various places throughoutthis specification are not necessarily all referring to the sameembodiment, but may. Furthermore, the particular features, structures orcharacteristics may be combined in any suitable manner, as would beapparent to one of ordinary skill in the art from this disclosure, inone or more embodiments.

Similarly it should be appreciated that in the description of exemplaryembodiments of the invention, various features of the invention aresometimes grouped together in a single embodiment, figure, ordescription thereof for the purpose of streamlining the disclosure andaiding in the understanding of one or more of the various inventiveaspects. This method of disclosure, however, is not to be interpreted asreflecting an intention that the claimed invention requires morefeatures than are expressly recited in each claim. Rather, as thefollowing claims reflect, inventive aspects lie in less than allfeatures of a single foregoing disclosed embodiment. Thus, the claimsfollowing the detailed description are hereby expressly incorporatedinto this detailed description, with each claim standing on its own as aseparate embodiment of this invention.

Furthermore, while some embodiments described herein include some butnot other features included in other embodiments, combinations offeatures of different embodiments are meant to be within the scope ofthe invention, and form different embodiments, as would be understood bythose in the art. For example, in the following claims, any of theclaimed embodiments can be used in any combination.

In the description provided herein, numerous specific details are setforth. However, it is understood that embodiments of the invention maybe practiced without these specific details. In other instances,well-known methods, structures and techniques have not been shown indetail in order not to obscure an understanding of this description.

Where in embodiments of the present invention reference is made to anoptical lens device, reference may be made to an optical device having alensing effect, for example a refractive element, a diffractive elementor a Fresnel element. The optical lens device may provide controlledscattering.

In a first aspect, the present invention relates to an optical lensdevice having an actively controllable focal length. The optical lensdevice comprises an optical element with lensing effect which comprisesa plurality of regions. Each such region has a corresponding lensingpower for providing a corresponding focal length distinct from the focallength of at least one other region of the plurality of regions. Theoptical lens device also comprises at least one addressable opticalelement integrated in or provided on the element with lensing effect.The at least one addressable optical element is adapted for changing thetransmittance of at least one of the plurality of regions in response toa control signal. The at least one addressable optical element may beadapted for changing the ratio of the intensity of light transmittedthrough this at least one region over the intensity of light incident onthe at least one addressable optical element. Particularly, the at leastone addressable optical element may be adapted for changing the ratio ofthe fraction of light transmitted through a first region of theplurality of regions over the fraction of light transmitted through asecond region of the plurality of regions. The at least one addressableoptical element may be a non-concentric area. The non-concentric areamay be a non circle-symmetric sector of the optical element with lensingeffect. The non-concentric area may comprise one or more sector regionsof the optical element with lensing effect. The one or more sectorregions may be pie-slice shaped, e.g. having their pie-point in thecenter of the optical element with lensing effect. The optical lensdevice also comprises a control means for generating the control signal,e.g. for generating the control signal in order to select a focal lengthor combination, e.g. superposition, of focal lengths from the focallengths provided by the plurality of regions, for example, to select adioptre or optical correction.

The optical lens device according to embodiments of the presentinvention may be adapted for use as an ophthalmic contact lens or foruse as an intra-ocular implant. For example, a multifocal contact lenscan be provided in accordance with embodiments of the present inventionthat comprises addressable optical elements which may be incorporated inthe lens for selectively blocking or transmitting light throughdifferent zones of the lens. Thus, these different zones can providedifferent eye corrections, e.g. different dioptric powers. It is anadvantage of such embodiments of the present invention that an efficientand simple means for real-time adjustment of the diopter of anophthalmic lens is provided, e.g. without requiring complex elements,e.g. active lens elements with an adjustable shape and/or adjustablerefractive index. An ophthalmic lens according to embodiments of thepresent invention may be suitable for correcting nearby and far visionaccommodation, e.g. to overcome the effects of presbyopia. However,other lens corrections such as, but not limited to, astigmaticcorrection can also be implemented in a device according to embodimentsof the present invention.

For example, for an optical lens device intended for use as a contactlens, modern materials known in the art for either soft or rigid gaspermeable contact lenses may be used as base material for the elementwith lensing effect to provide good biocompatibility and a sufficientlyhigh oxygen transmissibility. It is an advantage of simple designs, e.g.the embodiment illustrated in FIG. 9 and FIG. 10, that few electro-opticcomponents and supporting electronic elements need to be provided on orembedded in such biocompatible substrate. Therefore, a good trade-offmay be achieved between an acceptable oxygen transmissibility and a goodmultifocal functionality. The element with lensing effect mayfurthermore be provided with a suitable coating for improving theproperties of the device for use as a contact lens, for example, may beprovided with a parylene coating, although embodiments are not limitedthereto.

However, an optical lens device according to embodiments of the presentinvention may also be suitable for other fields of application, e.g. foruse in an optical apparatus such as a photographic camera. Thus,embodiments of the present invention may advantageously enable theswitching of the optical apparatus, e.g. the photographic camera,between different focal distances, e.g. for zooming and focusing,without requiring mechanically moving parts, e.g. moving lens groups.

FIG. 1 and FIG. 2 show an optical lens device 1 according to embodimentsof the present invention. FIG. 1 shows a frontal view of such opticallens device 1, while FIG. 2 shows a transversal view, e.g. across-sectional view, of the optical lens device 1. The optical lensdevice 1 comprises an element with lensing element 2. In particularembodiments, the element with lensing effect 2 may be a lens, such as acircularly shaped lens. However, a lens having another rounded shape, arectangular shape or any other shape may also be within the scope ofembodiments of the present invention, as will be understood by theperson skilled in the art. The element with lensing effect may becomposed of a rigid gas permeable or soft material, e.g. a material asis known in the art as a suitable material for lenses, e.g. for contactlenses.

The element with lensing effect 2 comprises a plurality of regions, forexample two regions 3 a,3 b, although more than 2 regions, such as forexample 3, 4 or more regions also can be implemented. Each such region 3a,3 b has a corresponding refractive power for providing a correspondingfocal length distinct from the focal length of at least another regionof the plurality of regions, e.g. each region may have a distinctrefractive power and may thus provide a corresponding distinct focallength. The shape of these regions, e.g. of these individuallyselectable lens zones, may not be limited to a specific arrangement, butmay depend on design considerations for a particular application.

The element with lensing effect can be constructed in such a way thatthe different regions may have different optical powers. For example,FIG. 3 shows a simple illustrative embodiment where the element withlensing effect 2, e.g. an optical lens, comprises two regions thattogether constitute the whole element area. For example, in a contactlens, the first region 3 a may be constructed in such a way that itcorrects the vision for nearby vision while the second region 3 b maycorrect the vision for remote vision. By making region 3 a substantiallytransparent and region 3 b substantially opaque, as shown in FIG. 4,light entering the eye of the wearer will only be corrected for nearbyvision and the wearer will have sharp vision of nearby objects.Conversely, by making region 3 a opaque and region 3 b transparent, asshown in FIG. 5, the lens wearer will have essentially a sharp remotevision. The different optical behavior of the two regions may beestablished by having different lens curvatures in these two regions,e.g. a different curvature on the front side and/or on the back side ofthe refractive element 2, for example as shown in FIG. 2. Furthermore,the transition between such regions may constitute a discontinuity ofthe lens surface. However, in accordance with embodiments of the presentinvention, a smooth transition may be provided between adjacent regions3 a,3 b. Furthermore, a narrow opaque zone may be optionally arrangedbetween addressable optical elements corresponding to the adjacentregions 3 a,3 b, e.g. an opaque zone having a width sufficient formasking such a smooth transition zone. It is an advantage of such smoothtransition that unwanted effects due to sharp edges on the surface ofthe lens are avoided or reduced, e.g. hampering of the eye lid movementfor a contact lens.

Two exemplary possible arrangements for the regions of the element withlensing effect 2, in accordance with advantageous embodiments of thepresent invention, are shown in FIG. 6 and FIG. 7, which are furtherdiscussed hereinbelow. However, other arrangements or shapes of theareas may also fall within the scope of the present invention, oneexample thereof being as shown in FIG. 8, and such arrangements orshapes of the area may be chosen appropriately for a particular intendedapplication, as will be understood by the person skilled in the art.

Although the different optical power regions may be created usingrefractive optics with different surface curvatures, such regions mayalso be implemented using other effects. For example, a material with agradient in the refractive index may be used in order to achieverefraction and locally varying focal length without introducing surfacecurvature. For example, the element with lensing effect 2 may be agradient index (GRIN) lens. It is an advantage of such gradient indexlenses that the regions having different dioptric power can bejuxtaposed without a discontinuity in the shape of the lens surface.

Alternatively or in addition thereto, the element with lensing effect 2may comprise a diffractive optical element, for example the element withlensing effect 2 may be implemented by introducing microscopic topologyinto the topology of the lens, e.g. by providing microgrooves therein.In fact, any method or combination of methods that allow to produce alens with different lensing characteristics in different zones may besuitable for manufacturing an optical lens device according to thepresent invention.

The optical lens device 1 comprises at least one addressable opticalelement 4 integrated in or provided on the element with lensing effect2. For example, the at least one addressable optical element may beembedded into the element with lensing effect, e.g. embedded in the lenssuch as shown in FIG. 2, or may be placed in close proximity to theelement with lensing effect, e.g. arranged on the lens. A one-on-onecorrespondence may exist between the addressable optical elements andthe plurality of regions of the element with lensing effect, e.g.forming selectable lens zones.

The shape and arrangement of the at least one addressable opticalelement 4 may be determined by the shape and arrangement of theplurality of regions of the element with lensing effect. For example,the at least one addressable optical element may be arranged such as toprovide at least one selectable lens zone corresponding to at least oneregion of the element with lensing effect.

However, the union of all selectable zones, e.g. the total area spannedby the at least one addressable optical element may be smaller than thesurface area of the element with lensing effect, e.g. the at least oneaddressable optical element may not entirely cover the element withlensing effect. For example, FIG. 8 shows an arrangement in whichregions 41 and 42 of the element with lensing effect are provided with acorresponding addressable optical element, while region 43 of theelement with lensing effect is not provided with an addressable opticalelement.

It is to be noted that the at least one addressable optical element maybe adapted for changing the ratio of the fraction of light transmittedthrough a first region of the plurality of regions over the fraction oflight transmitted through a second region of the plurality of regions.Therefore, if the cardinality of the regions of the element with lensingeffect equals N, N−1 addressable optical elements may suffice to adjustall pairwise transmission ratios for the N regions. The non-addressablezones, e.g. corresponding to the region 43 in the example shown in FIG.8, may be permanently transparent, permanently opaque or have anytransmission coefficient between 0 and 100%. This transmission may evenbe location dependent, so that gradual transmission patterns arepossible. Thus, any static transmission pattern may be implemented inthe non-addressable zones of the lens.

For example, in FIGS. 9 and 10 an exemplary embodiment is shown, similarto the optical lens device shown in FIG. 1 and FIG. 2, but whichcomprises only one addressable optical element 4. Because theaddressable optical element 4 only covers half of the lens, e.g. theright side as shown in FIG. 9, any absorption in the transparent state,for example due to polarization or other causes of sub-optimal behaviorof the addressable optical element, is avoided for the other half, e.g.the left side of the lens. Such optical device may enable the selectionof a single focus, corresponding to the focus of the left region 3 a, byblocking light transmission through the right region 3 b via theaddressable optical element 4, and the selection of a dual focus, e.g. asuperposition of the focus of the left and right regions 3 a,3 b, byallowing light transmission through the right region 3 b via theaddressable optical element 4. The situation For example, lighttransmitted in the latter configuration may be partly corrected forremote vision and partly for nearby vision. Although this has thedisadvantage of reduced contrast and ghost imaging, as would be the casein a conventional dual focus lens; the system may have an advantageouslyhigh optical transmission and is simple to implement since only oneaddressable optical element 4 has to be addressed. For applicationswhere it is sufficient to have one high-contrast state, this embodimentcould be preferable.

Furthermore, the at least one addressable optical element 4 may compriseoverlapping addressable zones. For example, two or more layers ofaddressable optical elements may be provided.

The at least one addressable optical element 4 is adapted for changingthe transmittance of at least one of the plurality of regions inresponse to a control signal. Thus, light may be selectively allowed topass through one or more lens zones in accordance with the controlsignal. Each such region 3 a,3 b has a corresponding refractive powerfor providing a corresponding focal length, therefore, a focus, orcombination of superimposed focuses, may be selected by substantiallyenabling or preventing the transmission of light through at least one ofthe plurality of regions in response to the control signal.

The transmission of the at least one addressable optical element 4 maybe selected in a range between a minimum transmittance value and amaximum transmittance value. The minimum value may be 0% or low enoughfor the intended application, for example 5% or 10%, or even 20%. Themaximum value may be 100% or high enough for the intended application,e.g. 95% or 70%, or even 40%.

The transmission of each of the at least one addressable optical element4 may be selected from a discrete number of values in this range, e.g.the transmission can be set to either 0% or 100%, or either 5% or 95%,or may be set to 0%, 50% or 100%. In embodiments of the presentinvention, the transmission of the at least one addressable opticalelement may even be selected from a continuity of intermediate statesbetween the minimum and the maximum transmittance value.

Each addressable optical element 4 may be implemented in such a way thatthe transmission inside the addressable zone covered by the addressableoptical element is essentially uniform. However, in embodimentsaccording to the present invention, an addressable optical element mayalso provide a transmission gradient. For example, such optionaltransmission gradients may be realized by incorporating a fixedtransmission pattern covering the addressable zones, but may also be theresult of a non-uniform operation of the addressable optical elements.

The at least one addressable optical element 4 may comprise a liquidcrystal (LC) technology element, such as, but not limited to, aguest-host LC, twisted nematic LC, vertically aligned nematic LC, hybridaligned nematic LC, in-plane-switching LC, ferroelectric LC orantiferroelectric LC element. The LC technology element can make use ofpolarization effects or not. It is an advantage of a non-polarizationbased LC technology element, such as a guest-host LC element, that ahigh maximum transmission can be achieved.

The at least one addressable optical element may also be based on otherelectro-optical effects for switching, e.g. with a discrete number or acontinuity of intermediate degrees, between substantially transparentand substantially opaque. For example, the at least one addressableoptical element may comprise an element using electrochromic behavior orelectrowetting. Furthermore, the at least one addressable opticalelement may comprise an element exhibiting a non-electricallyaddressable effect, such as, but not limited to, pressure-sensitivelight transmission elements or temperature-driven variable transmissionelements.

In particular advantageous embodiments, the at least one addressableoptical element may be bistable or multistable, such that energy is onlyneeded to change the transmission state, e.g. no energy is expended formaintaining the existing transmission state.

The at least one addressable optical element may comprise a powersupply. For example the at least one addressable optical element maycomprise an external power connection, e.g. the energy to power theaddressable optical elements may be provided by an electricalconnection. The addressable optical element may comprise an integratedbattery system, an integrated energy-harvesting or scavenging system ormay receive power via wireless transmission of energy, e.g. using radiofrequency radiation, inductive coupling, light or another wirelesscarrier of energy. Furthermore, a combination of such means for powersupply may also be used, e.g. a battery system that can be rechargedusing an inductive energy coupling system.

FIG. 6 shows an arrangement of the regions of the element with lensingeffect of an optical lens device according to a first exemplaryembodiment in one aspect of the present invention. In this exemplaryembodiment, the plurality of regions of the element with lensing effectmay comprise regions arranged as concentric rings 21, e.g. concentricaround the central optical axis of the element with lensing effect.Furthermore, the plurality of regions of the element with lensing effectmay comprise the central circular zone 22. Such arrangement may be knownin, for example, contact lens design, e.g. to produce static multifocallenses. Therefore, the element with lensing effect may be a staticmultifocal lens, e.g. an ophthalmic multifocal lens as known in the art.

For application of the optical lens device according to this embodimentin a contact lens, it is noted that, under bright circumstances, the eyepupil has a small diameter. Although the pupil may be separated from thelens by a few millimeters, the central region of the lens may primarilycontribute to the vision under such bright circumstances. In dimlighting circumstances, the pupil has a larger diameter, and thecontribution of the outer rings may become relatively more importantthan that of the central part of the lens.

However, without the active shading provided by the present invention, asimilar concentrically arranged multifocal lens would depend on afunctional relationship between the perceived brightness and theappropriate focal distance. The present invention overcomes thislimitation by incorporating at least one addressable optical elementwhich enables to effectively select the active lens regions, independentof the brightness level. For example, the at least one addressableoptical element may comprise one or more concentric elements, e.g.concentric annular elements optionally including a central circularelement, arranged such as to correspond to the concentric ring regions21 or central regions 22 of the element with lensing effect.

Therefore, it is an advantage of embodiments of the present inventionthat focus selection can be achieved in a contact lens without assuminga brightness-focal distance relationship. It is furthermore an advantagethat a default mode of operation may involve using such contact lens ina passive mode, in which pupil dilation can select a default focus as isknown for static multifocal contact lenses. However, if the userperceives an incorrect focus selection, e.g. while attempting to read abook under very bright conditions, or while observing a panoramic viewunder dim lighting conditions, the user can operate the control means inorder to select the correct focus in accordance with embodiments of thepresent invention. Therefore, embodiments provide the further advantageof enabling a power efficient focus selection when combining a passivedefault mode with a powered, active focus selection for correcting thedefault. This furthermore has the advantage of requiring little userintervention, e.g. only requiring a control command when the defaultfocus corresponding to the conventional passive multifocal lensoperation is not suitable.

Even though the varying pupil diameter may reduce the effectiveness ofthe outer zones in an optical lens device arranged as shown in FIG. 6,e.g. the outer zones can only contribute to image formation in dimlighting circumstances, this may be overcome by normal pupil dilation.Since incident light can be blocked at the center if one of the outerregions is actively selected in accordance with embodiments of thepresent invention, this can cause the pupil to dilate in response, suchthat the outer zones can contribute as intended to the image formation.

FIG. 7 shows an optical lens device according to a second exemplaryembodiment of the present invention. Here, the regions of the elementwith lensing effect may comprise at least one lens sector 31.Embodiments in accordance with such arrangement have the advantage ofbeing insensitive to a diaphragm selection, e.g. to the variable pupildiameter for an ophthalmic contact lens, since each region extendssubstantially to the optical center of the element with lensing effect,e.g. each sector has a tip positioned inside the smallest possible pupilarea.

In FIG. 11, another embodiment according to the present invention isshown. Here, an aspheric multifocal design is illustrated, in which theoptical transmission across the entire element with lensing effect 2 canbe tuned by the incorporation of an array of addressable opticalelements 4. The optical lens device is provided with a rectangular arrayof addressable elements as shown, similar to a matrix display device,with which an arbitrary transmission pattern can be established withinthe resolution limits provided by this array. The element with lensingeffect 2 may be an aspheric multifocal lens, e.g. as shown in FIG. 12.Here, a continuously varying refractive power and corresponding focallength are provided by an aspheric curvature of the lens surface. Thus,any local neighbourhood of a point on the element with lensing effect 2constitutes a region having a corresponding refractive power forproviding a corresponding focal length distinct from the focal length ofanother region, e.g. a local neighbourhood of a different point on theelement with lensing effect 2. In other words, the element with lensingeffect 2 may comprise an uncountable plurality of regions, each regionhaving a corresponding refractive power for providing a correspondingfocal length distinct from the focal length of at least one other regionof said plurality of regions.

FIG. 13 shows an optical lens device 1 comprising addressable opticalelements 4 arranged in concentric addressable rings. Therefore, suchdevice allows the selection of any axial-symmetric transmission pattern.The optical lens device further comprises, similarly to the previousexample in FIG. 11 and FIG. 12, an aspheric element with lensing effect2, e.g. shown in FIG. 14, having a varying optical power as a functionof the distance from the center point. For example, the device may focuson a near, middle or far point depending on where the light transmissionis allowed. In addition, more complex patterns can be applied byadministering a gradient in the transmission in the lens. This caneasily be implemented if the optically addressable elements can haveintermediate transmission states. Thus, a detailed balance can beachieved between image formation of nearby, medium distance or distantfeatures. Moreover, by tuning the overall transmittance of the lens, thepupil size can be affected and pupil size induced blur can thus beminimized. This principle can also be applied to different embodiments,as will be apparent to the person skilled in the art.

An optical lens device according to embodiments of the present inventionalso comprises a control means 5 for generating the control signal forthe least one addressable optical element. This control signal may betransmitted through a conductive path, e.g. the control means may beprovided in or on the element with lensing effect by, for example,semiconductor processing, and may be connected to the at least oneaddressable optical element via an integrated connection, e.g. as shownin FIG. 1. Alternatively, the control means may communicate wirelesslywith the at least one addressable optical element, e.g. via radiofrequency transmission or via optical signaling, e.g. as illustrated inFIG. 11.

In embodiments where the control means is integrated in or on theelement with lensing effect, such control means may receive commands viaeye lid gestures or pressure signals provided via the closed eyelid. Forexample, such commands may comprise blinking 2 times within 1 second,keeping the eye closed for 1 second or pressing on the lens through theclosed eyelid. The control means may comprise a sensing circuit insidethe lens for detecting such gestures and control the addressable opticalelements accordingly.

The processing of the input data and determination of the appropriatecommand of the optical elements can be performed by an integratedelectronic circuit, although embodiments of the present invention arenot limited thereto. This circuit can be made using thin-film technologyor silicon technology. In the latter case, the silicon chip can beembedded into or onto the lens using techniques such as, or similar to,ultra-thin chip packaging (UTCP). In the former case, the circuit can beintegrated on the same carrier substrate as the addressable opticalelements or on another, dedicated, carrier substrate that can beintegrated into or onto the lens together with the optical elements.

Particularly, in the case of bistable or multistable addressable opticalelements, the control means may comprise an external power source, whichwhen brought into an effective range of power transmission, e.g. viainduction, triggers a state change of the bistable or multistableaddressable optical elements. It is an advantage of such embodiments,and particularly of such embodiments comprising only a singleaddressable optical element, that the control circuitry required in oron the element with lensing effect can be simple, robust and low cost.

In a second aspect, the present invention relates to a method 100 forcontrolling the focal length of an optical lens device, e.g.advantageously an optical lens device 1 according to the first aspect ofthe present invention. An exemplary method 100 according to this secondaspect of the invention is illustrated in FIG. 15. This method 100comprises providing 101 an element with lensing effect 2 comprising aplurality of regions 3 a,3 b, in which each region has a correspondingrefractive power for providing a corresponding focal length distinctfrom the focal length of at least one other region of the plurality ofregions. The method further comprises changing 102 the transmittance ofat least one of the plurality of regions by controlling at least oneaddressable optical element 4 integrated in or provided on the elementwith lensing effect 2. Details with respect to such an exemplary methodwill be clear to the person skilled in the art in the light of thedescription of the first aspect of the present invention providedhereinabove. Moreover, such a method may comprise steps expressing thefunctionality of devices, components and/or arrangements of devicesaccording to embodiments of the present invention.

The present invention also relates to the use of an optical lens device1 according to the first aspect of the present invention for humanvision correction, e.g. as contact lens or intra-ocular implant. Forexample, the present invention also relates to the use of an opticallens device 1 according to the first aspect of the present invention forcorrection of presbyopia.

In a further aspect, the present invention also relates to an opticallens device having the same features as described for the optical lensdevice of the first aspect, but restricted by its surface area. The atleast one addressable optical element has a lens surface area being atleast 10%, e.g at least 15%, e.g. at least 20% of the surface area ofthe optical element with lensing effect. The shape thus may be anysuitable shape such as for example, one or more sectors, a concentricshape e.g. one or more concentric rings, a disc shape, etc. Otherfeatures thus may be as described in any of the earlier discussedembodiments.

The invention claimed is:
 1. An optical lens device having an activelycontrollable focal length, comprising: an element with lensing effectcomprising a plurality of regions, each region having a correspondingrefractive power arranged for providing a corresponding focal lengthdistinct from the focal length of at least one other region of saidplurality of regions; at least one addressable optical elementintegrated in or provided on the element with lensing effect, the atleast one addressable optical element being arranged for changing thetransmittance of at least one of said plurality of regions in responseto a control signal; and a control means programmed for generating saidcontrol signal, wherein said at least one addressable optical element isnon-concentric, said at least one addressable optical element comprisingan addressable optical element configured as one or more sectors of theelement with lensing effect, wherein the one or more sectors arepie-slice shaped sectors with their pie-point at the centre of theelement with lensing effect.
 2. An optical lens device according toclaim 1, wherein said optical lens device is adapted for use as anophthalmic contact lens or an intra-ocular implant.
 3. An optical lensdevice according to claim 1, wherein the shape and arrangement of the atleast one addressable optical element is determined by the shape andarrangement of the plurality of regions of the element with lensingeffect.
 4. An optical lens device according to claim 1, wherein acorresponding addressable optical element is provided in or on each ofsaid plurality of regions.
 5. An optical lens device according to claim1, wherein said element with lensing effect is made of rigid gaspermeable or soft material.
 6. An optical lens device according to claim1, wherein said at least one addressable optical element comprises asurface area of at least 10% of the surface area of the element withlensing effect.
 7. An optical lens device according to claim 1, whereinsaid at least one addressable optical element covers an area which issubstantially less than the total area of the element with lensingeffect.
 8. An optical lens device according to claim 1, wherein said atleast one addressable optical element comprises overlapping layers. 9.An optical lens device according to claim 1, wherein said at least oneaddressable optical element comprises a liquid crystal technologyelement.
 10. An optical lens device according to claim 1, wherein saidat least one addressable optical element comprises a bistable ormultistable element.
 11. An optical lens device according to claim 1,wherein the at least one addressable optical element comprises an energysupply.
 12. The use of an optical lens device according to claim 1 forhuman vision correction.
 13. A method for controlling the focal lengthof an optical lens device, comprising: providing an element with lensingeffect comprising a plurality of regions, each region having acorresponding refractive power for providing a corresponding focallength distinct from the focal length of at least one other region ofsaid plurality of regions; and changing the transmittance of at leastone of said plurality of regions by controlling at least one addressableoptical element integrated in or provided on the element with lensingeffect, said at least one of said plurality of regions, wherein the atleast one sector shape is a pie-slice shaped sector with its pie-pointat the centre of the element with lensing effect.